A young worker grinds off the sharp edges from a mortar shell that will be filled, assembled and shipped to the front lines from this location in northern Syria, on June 22, 2013. This young laborer works in an underground factory that produces munitions for one of the most powerful Free Syrian Army brigades in the area, The Ahrar Suriyah. This factory is so secret that most of the fighters have no clue that it exists.

Abu Ala, 23, works on machine a mortar shell as his older brother manages other workers in the factory on June 22, 2013. Abu Ala and his three brothers run this secret weapons factory for the Ahrar Suriyah brigade. Abu Ala and his brothers were foremen in a factory in Beirut before coming back to Syria to support the revolution.

Unloaded shotgun shells are placed in the mortars and used to ignite the propellant packs that are wrapped around the base of the mortar before they are fired on June 22, 2013. These mortars are hand assembled in this factory and shipped out to fighters all over northern Syria.

A young factory worker machines small fuses for the mortars on June 22, 2013. This factory, with its outdated equipment, can manufacture around 50 mortar shells in a 14-hour-period.

Syrian-made grenades made from salvaged water pipes and sealed with yellow wax, lay on the ground next to explosive mixture that they are packed with, in a secret arms factory in northern Syria on June 22, 2013. This factory is able to produce 1000 of these grenades a day.

Abu Abdul, 30, assembles the bodies to what will eventually become prototype rockets that the Free Syrian Army has started to manufacture and test, in Aleppo, Syria on June 22, 2013.

A Free Syrian Army fighter, formerly an officer in the Syrian Army, takes cover as he prepares to fire a Syrian-made mortar at a regime-held position in northern Syria on June 22, 2013.

A spotter watches for the impact of the mortar shell as other fighters take cover and prepare for the regime to retaliate in northern Syria on June 22, 2013. Without the help of the international community, the Free Syrian Army and other rebel groups have used what resources they have available to them to match firepower with the Russian, Iranian and Hezbollah-backed regime forces.